I have a workaround you could consider. I have a bit of javascript that loops through all img elements nested inside a menu. The script enables you to change the most recently clicked img. The only change I have found necessary for my use is to highlight the recently clicked img with a 2px border. Simply add the javascript (and two style rules)in the head of your template and the script will dynamically find img inside a menu.
You can grab the script here
http://blomhansen.net/test/setCurrent.htm
If you need help with adding the script to your template, post a question.
Maybe we can help eachother? Please describe how you get the simple image module to display an image and a rollover - I have installed the module but cannot get it to work. I am convinced I am doing something wrong, but I dont know what?
Kind regards
Thomas